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Coordinate Geometry

Question
CBSEENMA9001860

Write the following cubes in expanded form:

open parentheses straight x minus 2 over 3 straight y close parentheses cubed

Solution
open parentheses straight x minus 2 over 3 straight y close parentheses cubed equals x cubed minus open parentheses 2 over 3 y close parentheses cubed minus 3 left parenthesis x right parenthesis open parentheses 2 over 3 y close parentheses open parentheses x minus 2 over 3 y close parentheses
                                          | Using Identity VII
equals space straight x cubed minus 8 over 27 straight y cubed minus 2 xy open parentheses straight x minus 2 over 3 straight y close parentheses
equals space straight x cubed minus 8 over 27 straight y cubed minus 2 straight x squared straight y plus 4 over 3 xy squared
equals space straight x cubed minus 2 straight x squared straight y plus 4 over 3 xy squared minus 8 over 27 straight y cubed.